In recent years, a glass substrate that is used in a display panel such as a liquid crystal display panel has been increasing in size (8th generation: 2160 mm by 2460 mm). For keeping and carrying such a large glass substrate in a display panel factory, a substrate storage tray disclosed in Patent Literature 1 is used, for example.
As shown in FIG. 7, each substrate storage tray 101 includes a rectangular bottom portion 101a on which a glass substrate 20 is horizontally placed, and a rim portion 101b that projects upward from the edges of the bottom portion 101a. 
As shown in FIG. 7, the substrate storage trays 101 that are vertically stacked on a pallet 102 each store the glass substrates 20 with their processed surfaces 20a facing upward. The bottom portion 101a of each substrate storage tray 101 includes pin insert holes 101c that are openings into which substrate support pins (not shown) are inserted from beneath.
A description of the process of taking out the glass substrates 20 from the substrate storage trays 101 that are vertically stacked as described above is provided. First, the substrate storage trays 101 except for the lowest substrate storage tray 101 are lifted up.
Then, the substrate support pins (not shown) are inserted into the pin insert holes 101c of the lowest substrate storage tray 101 so as to raise the glass substrate 20 from the bottom portion 101a of the lowest substrate storage tray 101.
Then, the lowest glass substrate 20 that is being raised is taken out with the use of a substrate conveying arm (not shown). The lifted up substrate storage trays 101 are then lifted down. In this manner, the lowest glass substrate 20 is taken out from the lowest substrate storage tray 101. Through repetition of this process, the glass substrates 20 can be taken out one by one from the stacked substrate storage trays 101 so as to be conveyed to a given process line.